Lubricants



senate han: nonnrcan'rs Murray H. Schwartz, mileage. EL, assigns: to

Standard Oil tlon oi l. 1

No Drawing. AD Serial Claims.

l This invention relates to improved lubricants. More particularly it relates to compounded oils which have, in addition to valuable lubricating properties, the property of preventing corrosion on metal surfaces.

Engines which are exposed without operation to the atmosphere for considerable periods of time develop considerable corrosion. so that irequently they become inoperable or operate with greatly reduced eficiency for a shorter useful operating liie.

pilcation' July Gompsny, Chicago, lit, a corpora- The above observations apply'wlth particular force to engines exposed to severely corrosive atmospheres, such as are encountered, for example, on shipboard, in coastal areas, and in many industrial areas. Engines in military equipment are often subjected to storage in corrosive atmospheres for long periods of time, for example in transoceanlc shipping. Furthermore, the operation or internal combustion engines, especially spark ignition engines, results in the production of gases which corrode various metal engine parts with which they come in contact. Particularly corrosive gases are generated in the operation oi internal combustion engines upon fuels containing ethyl fluid.

' quarters of their area in 160 grams of the rust Heretoiore it has been proposed to protect metal surfaces from corrosion by the use of readily removable protective coatings, known as slushlng compounds. Slushing compounds are petro= leum rust preventives and are usually classifiedas oils and greases, from the standpoints of appearance, handling and service properties.

Lubricating oils which can also be used as a rust preventive for internal combustion-engines,

in addition to meeting the usual specifications concerning viscosity, volatility and pour point, must have four main properties;

(1) Ability to protect against high humidity and moisture condensation;

(2) A minimum eliect on all metals which may be included in an engine assembly;

(3) Ability to be readily applied to and removed from an engine assembly;

(i) Ability to neutralize acidic products of combustion in the engine.

It will be apparent that practical specifications based on the above properties can hardly be absolute in nature, but relative standards, represented by certain tests, have been offered and widely accepted. These tests will be described brieiiy. Unless otherwise indicated, all tests are carried out upon cold rolled, sandblasted S. A. E. 1020 steel panels, 2" x i" x i change in weight.

in the bottom of the cabinet to give approximately humidity at all times. The steel panels are coated by dipping into the rust preventive material and are suspended by glass hooks from a glass rod running across the top of the humidity cabinet. To insure that no moisture of condensation comes in contact with the steel panels, stainless steel shields are placed above the panels in such a position that no moisture iromthe shields can drip on the panels. From 1 to 1.5 complete changes of saturated air per hour are provided in the cabinet. A. satisfactory rust preventive should give a minimum of 200 hours protection to the steel panels in the humidity test.

In the test designed to evaluate the eiiects oi the rust preventive composition on metals, cleaned lead, copper, magnesium and steel panels, respectively, are immersed to the extent of threepreventive composition to which 1% of water has been added. After seven days storage at F. the change in weight of each panel is determined. In this test. coupled lead-steel panels also are tightly clamped together at an angle of approximately 30 degrees and immersed as described above. Panels of lead, copper and magnesium 2" x 4" x 4;" should not show more than 25 mg. Likewise coupled panels of lead-steel'should not show more than 35 mg. change in weight.

Thesalt water immersion testis designed to measure the ability of rust preventlves to protect metal parts against salt air or sea. water. In this test the steel panel is dipped in the rust preventive oil, allowed to drain for 24 hours at room temperature, and is then placed in a 3.5% salt solution for twenty hours. At the conclusion of this time the panel must show no evidence of corrosion. staining, or rust.

The hydrobromlc acid test is designed to measure the ability of the rust preventive oil to neutralize the acidic products of combustion of an internal combustion engine. In this test, the

steel panel is dipped in 0.1% aqueous hydroatlases at the conclusion of this time the panel must show no corrosion, staining or rust.

Hydrocarbon lubricating oils produced by conventional petroleum refining methods do not possess the combination of properties necessary for service both as lubricants and rust preventives. The observation is common that rusting can ocour on steel surfaces which have been coated with the usual straight mineral oils or petrolatums. In order to obtain the desired combination of properties, there has been a trend toward hydrocarbon oils compounded with various chemical agents, with more or less indifferent success.

Experience has shown that often the addition of a given reagent to a hydrocarbon lubricant results in the improvement of one desired property of the lubricant but exerts a deleterious e'f-- feet on one or more of the other desired properties, so that the net result is that it is disadvantageous to add the. reagent inouestlon to the lubricant. v

Although compounded oils satisfactorily exhibiting the first three properties described above have been producedtheyhave generally failed in the fourth property. I

My copending applicationSerial No. 500,277,

' filed August 27, 1943, or which the present appliof the copper-lead or cadmium-silver type, under operating conditions.

Accordingly, it is an object of the present 111-.-

. vention to provide a lubricant which is effective in preventing atmospheric corrosion as well as corrosion to internal parts of engines, particularly bearings of the hard metal alloy type, under operating conditions. Another object of this, invention is to provide a corrosion preventive lubricating composition for internal combustion engines, particularly spark ignition engines. Still another object of this invention is to provide a corrosion preventive characterized by the ability to neutralize acidic engine combustion products while retaining the other desirable properties of corrosion preventive lubricating composition 4- terpenes are sulfurized dipentene, sulfurlzed pine oil, sulfurized turpentine, sulfurized pinene, sulfurized terpenol, sulfurlred camphene and the like or mixtures of terpenes. I prefer to use 8111- furized .terpenes comprising a major part'of d1- pentenes. 4

The sulfurized terpenes can be prepared by sulfurlzing the desired terpene by any one of various sulfurization processes. Among the sulfurlzatlonprocesses which can suitably be employed is that of treating the terpene with sulfur and hydrogen sulfide in the presence of water or steam at temperatures within the range of about 250 F. to

450. F. and at pressures up to about 1500 pounds per square inch for a period of 1 to .10 hours. .The sulfurized terpene can also be prepared by treating the desired .terpene with a sulfur chloride, such as $2012 or 8012, at a temperature within the range of about 60 F. to about 250 F. When the terpene is sulfurized with a. sulfur chloride, the chlorine present in the sulfurlzed material can be removed by treating-the sulfurlubricants. Additional objects will become a parent as the description of. this invention proceeds.

I have found that compositions comprising a small proportion of a castor compound, a sulfurized terpene, a preferentially oil-soluble petroleum sulfonate and a hydrocarbon lubricating oil possess the combination of properties desired in corrosion preventive lubricants.

By a castor compound I means castor oil or its derivatives. Suitable castor compounds in-= clude castor oil, castor amide and-glycerol monoricinoleate. can be used successfully in my corrosion preventive lubricating composition, it is not intended to imply that they are all exactly equivalent in efficacy. In general, about 1% to about 10% of castor compound can be used, although some- Although many castor compounds,

' or other bases.

ized material in a bomb at a temperature of about 300 F. to about 400 F. with ammonia or other aqueous or alcoholic alkalies, alkali metal sultides and polysulfldes, such as a sodiumsulfide, The sulfurized terpenes which are best suited for the hereln-describedpurpose are those which have a sulfur content of from about 5% to about or more and which show slight sulfur activity, as defined below, at 210 F.

The sulfurized terpenesmay be characterized by their activity toward copper at various tom peratures. This may be empirically evaluated by immersinga polished copper strip in a mineral oil containing the sulfuriaed terpene and exam-. ining the strip periodically. The more desirable sulfurized terpenes show little activity toward copper at 210 F. when used in relatively low concentrations, e. g. up to 2% in oil, but quickly darken a copper strip at 300 F. when used in the same concentrations. The sulfurized terpenes containing active sulfur, as measured by rapid darkening of the copper strip at 300 F. are effective corrosion inhibitors in the engine when used in concentrations as low as 0.5%. Sulfurized terpenes containing less active sulfur are also effective corrosion inhibitors in the engine but ordinarily higher concentrations are required. The sulfur actlvity'of the sulfurized terpenes' may be increased by heating the sulfurized material to temperatures of from about 300 F. to about 450 F. Sulfur activity of the sulfurized terpenes can also be increased by distilling the sulfurlzed terpene under conditions whereby the high sulfurbearing fractions are concentrated in a 40% to what smaller or larger proportions can also be used.

v vIn general from about 0.1% to about 2% sulfurized terpene can be used. Suitable sulfur zed about bottoms. The sulfurized terpenes can also be concentrated by blowing the same with a gas at temperatures of about F. .to about 350 F. Sulfurlzed terpenes having a sulfur content above about 25% and preferably about 30% to about 40% or higher are most suitable when it is desired to employ low concentrations of the sulfurized terpenes in the finished lubricant.

Petroleum sulfonates are soaps 0t sulfonic acids obtained by the treatment of petroleum oils with strong sulfuric acid, usually fuming sulfurlc acid. The preferentially oil-solublesulfo'nic acids remain dissolved in the acid treated oil; they are commonly known as mahogany acids. Although a wide variety of mahogany soaps can be used for the purposes of this invention, I have found aeiaeae that they exhibit some variation in efficacy in my corrosion preventive lubricating compositions, depending on their method of preparation.

I have found that superior mahogany acids and soaps therefrom, for the purpose of this in vention, can be produced by treating distillates offrom about 50 seconds to about 1000 seconds or higher, and preferably from about 200 to about 850 seconds Saybolt Universal viscosity at 100 F. with from about 6 to about 9 pounds, and preferably from about '7 to about 8 pounds of concentrated sulfuric acid, preferably fuming sulfuric acid, per gallon of oil.

The method of obtaining these desirable soaps of preferentially oil-soluble sulionic acids derived from petroleum oils is illustrated by the following example, which describes the preparation of a sodium soap.

A petroleum oil distillate having a gSaybolt Universal viscosity at 100 F. of from about 200 seconds to about 850 seconds is treated with from about 7 to about 8 pounds of fuming sulfuric acid per gallonof oil in one-half pound increments-or dumps." After the acid sludge from each one-half pound acid dump" is settled and withdrawn, the next one-half pound of fuming sulfuric acid is added to the oil. The temperature of the oil before the fuming acid is added thereto is maintained below about 60 F. but due to the heat of reaction upon the addition of the sulfuric acid, the temperature of the oil may rise to from about 90 F. to about 100 F. After the required total amount of fuming sulfuric acid,

- of about 8 to about20%.

has been added to the oil and the oil freed of acid sludge, the acid treated oil'containing oilsoluble sulfonic acids dissolved therein, is neutralized with a solution of sodium hydroxide.

The aqueous alkali solution is then separated from the oil solution containing dissolved therein sodium soap of sulfonic acids and the latter then separated from the oil by extraction with alcohol of about 60% strength. The alcohol layer containing dissolved sodium sulfonates is then separated from the oil and subsequently distilled to recover the alcohol and remove water. The crude sulionic soap obtained in this manner contains from about 30% to about 60% sodium sulfonate, from about 30% to about 60% oil, from about 1% to about 10% water, and up to 10% of. inorganic salts which may be rembved by the procedure hereinafter described.

The above procedure may be modified after the Suitable soaps of preferentially oil-soluble petroleum sulfonic acids include those of metals in groups I; II, III, IV, VI and VIII of the periodic table. Thus, for example, I can employ the sodium, potassium, lithium, calcium, barium, tin,

lead, aluminum, chromium, cobalt and nickel soaps of preferentially oil-soluble petroleum sulfonic acids. I can also employ the ammonium, al-

kylammonium and alkylolamine soaps of preferentially oil-soluble petroleum sulfonic acids. It is not intended to imply that the wide variety of sulfonates mentioned above are exactly e uivalent for the purpose of my corrosion preventive lubricating compositions. tive cheapness and high emcacy I prefer to use the sodium soaps, especially the sodium soaps of the preferred mahogany acids whose preparation has been described above. I

The exact proportion of petroleum sulfonate to be used in my corrosion preventive lubricating; compositions will vary with the particular sulj' 'fonate chosen for use and upon the. severityof the service conditions which are anticipated. In

general, Ihave foundthat a useful range of pe troleum sulfonate is about 20% to about 40%,,the

actual sulfonate soap content being in the range I can use .any one of a wide variety of hydr carbon lubricating oils. The hydrocarbon l bricating oil can be a pure or relatively pure individual hydrocarbon or a definite hydrocarbonig mixture, or the complex mixture of hydrocarbons which constitute the lubricating oils produced in conventional petroleum refining operations. The choice of the particular oil to be'used will depend on the viscosity desired and the lubricating qualities of the oil and the viscosity desired'in the corrosion preventive lubricating composition. In

general, I can satisfactorily :use petroleum lubri cating oils having a viscosity in the range of about to about 80 seconds Saybolt Universal at 210 F.

Although slushing compounds which have previously been prepared by compounding mahogany sulfonates with mineral oil's affords some measure of protection against corrosion on metal surfaces and exhibit the first three of the four properties mainly desired in corrosion preventive lubricating compositions, "as described above, they fail completely to neutralize acid products,

i such as acidic products of combination in inacid sludge is removed from the acid treated oil.

sulfonic acids which may then neutralized with sodium hydroxide and subsequently freed of the alcohol by distillation.

The crude soaps of these preferentially oilsoluble sulfonic acids obtained by the procedure described above may be freed of inorganic salts by purification. This purification is preferably accomplished by dilution of the crude soap with from about V2 to about 10 parts, preferably 1 to 2 parts of 50% or higher strength-alcohol, prefer; ably alcohol of to strength, and allowing the salts to settle while maintaining the mixture within the temperature range of to 17551 preferably to F. When the salts have settledthe supernatant alcohol-soap layer is sep aratecl and the alcohol is recovered by conventional distillation procedure. By this method of purification the salt content of the crude sulfonic soap can be readily reduced to 5% or less, e. g., to about 3.5%.

ternai combustion engines, and fail to prevent substantial corrosion to the bearings of the hard metal alloy type.

, Illustrative of lubricant compositions of the herein-described invention are the following:

Example I Example II Per cent Per :e nt Castoroil. 2.0 -2.0 Sodium mahogany soap. 30.0 3;);0 Suliurized terpene 0. 5 0. 75 Hydrocarbonoil........... 07.5 67.25

' bearing loss of about 0.21 gram per whole bear-- ing. A satisfactory lubricant composition is one Because of their rela- 7 I I which will prevent a bearing loss of more than 0.5 gram per-full bearing.

The bearing loss is determined by subjecting {the lubricant to a modified so-called "36 hour I Chevrolet test, made in accordance with the Cooperative Research Council Test Procedure C. R. C. Designation L-4-243 of February, 1943. testv is madein. a six cylinderspark-ignition internal combustion engine equipped with two copper-lead alloy bearings and operating at about 3150 R. P. M. with an oil temperature of 250 F2 F., for grade oils, and 265 F.- -2 F. for 30 grade oils. The copper-lead alloy bearings areweighed before the test and at the end of the test period and the amount of corrosion expressed in grams per full hearing loss durin the test period.

In addition to the hereinbefore-mentioned additives, the lubricant compositions can include polymeric thickeners, viscosity index improvers, oiliness agents, pour point depressants, antioxi-' dants for castor oil compounds, antioxidants for hydrocarbon oils. etc.

The herein-described lubricant compositions are not Only applicable to the protection of the interiors of internal combustion engines but are also applicable generally to the protection of metal surfaces as in gun barrels, metal containers, idle machinery, finished machine parts and accessories in storage, stand-by or emergency equipment, etc.

While I have described my invention by reference to certain preferred embodiments thereof,

the same has been given by way of illustration only and is not intended to be a limitation of the scope of the invention except in so far as the .oil.

6. A composition of matter comprising about aeiaiosa 0.1% to about 2% of a sulfurized terpene and a major proportion of a hydrocarbon lubricating 20% to about 40% of a soap of a preferentially oil-soluble sulfonic acid produced by treating a petroleum distillate having aviscosity in the range of about 50 to about 1000 seconds Saybolt Universal at 100 F.- with from about 6 to about 9 pounds of strong sulfuric acid. and about 1% to about 10% of a castor compound selected from the group consisting of castor oil, castor amide and glycerol monoricinoleate, about 0.1 to about 2% of a sulfurized terpene, and a major proportion of a hydrocarbon lubricating oil.

7. A composition of matter comprising about 20% to about of a soap of a preferentially oil-=soluble sulfonic acid produced by treating a petroleum distillate having a viscosity in the range of about 50 to about 1000 seconds Saybolt Universal at 100 F. with from about 6 to about 9 pounds of strong sulfuric acid, about 1% to about 10% of castor oil, about 0.1% to about 2% of 'a sulfurized terpene, and a major proportion of 25 a hydrocarbon lubricating oil.

8. A composition of matter comprising about 20% to about 40% of a soap of a preferentially oil-soluble sulfonicacid produced by treating a petroleum distillate having a viscosity in the range of about 50 to about 1000 seconds Saybolt Universal at 100 F. with from about 6 to about 9 pounds of strong sulfuric acid, about 1% to about 10% of a castor amide, about 0.1% to about 2% of a sulfurized terpene. and a major proportion of a hydrocarbon lubricating oil.

9. A composition of matter comprising about 20% to about 40% of a soap of a preferentially oil-soluble sulfonic acid produced by treating a 2. A composition of matter comprising from about 8% to about 20% of a soap of a preferentially oil-soluble petroleum sulfonic acid, from about 1% to about 10% of a castor compound selected from the group consisting of castor oil, castor amide, and glycerol monoricinoleate, from about 0.1% to about 2% of a sulfurized terpene and a major proportion of a hydrocarbon lubricating oil. l

3'. A composition of matter comprising from about 8% to about 20% of a soap of a prefer-- entially oil-soluble petroleum sulfonic acid, from about 1% to about 10% castor oil, from about 0.1% to about 2% of a sulfurized terpene and a major proportion of a hydrocarbon lubricating oil.

4. A composition of matter comprising. from about 8% to about 20% of a soap of a preferentially oil-soluble petroleum sulfonic acid, from about, 1% to about 10% castor amide, from about 0.1% to about 2% of a sulfurized terpene and a major proportion of a hydrocarbon lubricating oil.

5. -A compositionof matter comprising from 8% to about 20% of a soap of a preferentially oilsoluble petroleum sulfonic acid, from about 1% to about 10% glycerol monoricinoleate', from about petroleum distillate having a viscosity in the range of about 50 to about 1000 seconds Saybolt Universal at F. with from about 6 to about 9 pounds of strong sulfuric acid, about 1% to about 10% of glycerol mono'ricinoleate, about 0.1% to about 2% of a sulfurized terpene exhibiting high sulfur acivity at a temperature of about 300 F. and higher, and a major proportion of a hydrocarbon lubricating oil.

10. A composition of matter comprising about 20% to about 40% of a sodium soap of a preferentially oil-soluble sulfonic acid produced by treating a petroleum distillate having a viscosity in the range of about 50 to about 1000 seconds Saybolt Universal at 100 F. with from about 6 to about 9 pounds of strong sulfuric acid, about 1% to about 10% of a castor compound selected from the group consisting of castor oil, castor amide and glycerol monoricinoleate, about 0.1% to about 2% of a sulfurized terpene exhibiting high sulfur activity at a temperature of about 300 F. and higher, and a major proportion of a hydrocarbon lubricating oil.

11. A composition of matter comprising about 20% to about 40% of a sodium soap of a prefer entially oil-soluble suifonic acid produced by treating a petroleum distillate having a viscosity in the range of about 50 to about 1000 seconds Saybolt Universal at 100 F. with from about 6 to about 9 pounds of strong sulfuric acid, about sulfur activityat a temperature of about 300 F.

and higher, and a major proportion of a hydrocarbon'lubricating oil.

12. A composition of matter comprising-about. I

20% to about 40% of a sodium soap of a preferaeraeae entially oil-soluble. sulronic acid produced by treating a petroleum distillate having a viscosity in the range of about 50 to about 1000 seconds Saybolt Universal at 100 F. with from about 6 to about 9 pounds of strong sulfuric acid, about 1% to about 10% of castor amide, about 011% to about 2% of a sulfurized terpene exhibiting high sulfur activity at a temperature of about 300 F. and higher, and a major proportion of a hydrocarbon lubricating oil.

13. A composition oi matter comprising about to about of a sodium soap 0! a preferentially oil-soluble sulfonic acid produced by treating a petroleum distillate having a viscosity in the range of about to about 1000 seconds Saybolt Universal at F. with from about 6 claim 1- in which the soap of a preferentially oil-' soluble petroleum sulfonic acid is a sodium soap of a preferentially oil-soluble petroleum sulfonic acid.

15. A composition as described in claim 2, in which the soap oi? a preferentially oil-soluble petroleum sulfonic acid is a sodium soap of a preferentially oil-soluble petroleum sulfonic acid.

L. SCHWARTZ. 

